Injection of water into oil producing formations has long been used for recovery of additional hydrocarbon values from such formations. The water used for such purposes may be produced water such as from the oil bearing formation or other subterranean water source, surface water and/or, particularly in an offshore environment, seawater. Such water generally contains large amounts of dissolved oxygen which, if not removed, will accelerate corrosion of oil field process equipment. Additionally, the products of such corrosion have an additional deleterious effect in that they can lead to plugging of the subterranean formation through gelation of various hydrated metal oxides.
For the above reasons, it has been common in the prior art to remove the dissolved oxygen from injection waters in order to avoid the corrosion and formation plugging potential of untreated water. Two of the most common methods are chemical deoxygenation and vacuum stripping. However, chemical systems are often incompatible with other well treatment fluids and may create additional suspended solids which are introduced into treating waters which adversely affect the hydrocarbon-bearing formation. The equipment employed in a vacuum deoxygenation operation comprises heavy, bulky and costly vacuum towers and pumping equipment. These disadvantages of the vacuum deoxygenation system employed on an offshore platform greatly increase the size and cost of such an installation, both in terms of the deoxygenator and the platform itself.
As an alternative to the above-noted chemical and mechanical processes for deoxygenating water, catalytic reduction of oxygen with hydrogen in the presence of a reduction catalyst has been suggested. In such a process, gaseous hydrogen is mixed with the water to be treated and passed over a bed of catalytic material. One particular type of catalyst preferred for this process is a palladium coated anion exchange resin produced by Bayer Chemical Company in Germany and sold as "Lewatit OC-1045". A biocide is also commonly added to the system in order to prevent bacterial growth on the resin. This process has the disadvantage of storage and transfer of highly explosive hydrogen as well as storage of a potentially dangerous and corrosive biocide, commonly chlorine.